Snow vehicle

Abstract: A snow vehicle comprises at least one runner (20, 20'; 54) by way of a ski which is mounted in such a way that it can be tilted and/or steered by means of manual tilting and/or steering members (5) connected actively to actuators (17, 18, 22, 17', 18', 22'; 153) for tilting and/or steering the runner (20, 20'; 54). In order to ensure greater ease, accuracy and reliability of steering, the invention provides that the manual tilting and/or steering member (5) is connected to the runner (20, 20', 54) tilting and/or steering actuator (17, 18, 22, 17', 18', 22'; 153) by means of a transmission system (30, 26, 27, 126, 127, 26', 27', 126', 127'; 60, 61, 60', 65, 66, 67, 67') constructed in such a way as to be mechanically rigid, i.e. with little or no play relative to the position of tilting and/or steering. The vehicle may be of the so-called snowmobile kind, or else a vehicle with no means of propulsion and adapted only to descent, similar to a skibob. The invention also includes further improvements to the structure of the frame of a snow vehicle.

Description: The invention relates to a snow vehicle comprising a load-bearing frame and two ski-like parallel runners which are connected with the load-bearing frame by means of runner-carrying arms in such a way that they can be steered and/or tilted by means of a control shaft which can be rotated manually through hand grip means and is connected by means of a transmission system with a steering and/or tilting shaft fixed to each runner and rotatably supported by the associated runner-carrying arm, the said transmission system comprising for each runner a pair of opposing transmission cables which engage on opposite sides of the longitudinal axis of the vehicle a control pulley rotating integrally with the control shaft, said cables being connected on opposite sides of the longitudinal axis of the associated runner with an actuating pulley that rotates integrally with the steering and/or tilting shaft of the runner. A snow vehicle of this kind is known from the document FR-A-2672504, according to which the ski-like runners are connected with the vehicle frame by means of elastically flexible runner-carrying arms. The document FR-A-2166780 describes a single runner snow vehicle, in which the runner is pivoted to the lower end of a vertical rotatable steering tube by means of longitudinal and a transversal pivot axis. The documents US-A-3107923 and CH-A-644557 disclose snow vehicles, in which the runner-carrying arms are connected with the vehicle frame by means of articulated parallelograms, which are deformed by manually rotating the hand grip means for steering and/or tilting the runners, without any other actuating means connecting the runners with the rotatable hand grip means. The purpose of the invention is to improve a snow vehicle of the kind described at the outset and in the preamble of claim 1, by using simple means and a robust, lightweight and relatively inexpensive construction to achieve the greatest possible comfort and ease of use and the utmost steering reliability. The invention achieves the above aims by a snow vehicle according to the preamble of claim 1 and characterized in that the runner-carrying arms are supported at the transverse ends of a front carriage subframe in the form of an articulated parallelogram which comprises two transverse arms positioned vertically one above the other and hinged at their mid points to the load-bearing part of the frame, in such a way that they can pivot about axes parallel with the longitudinal axis of the vehicle, the lower longitudinal arm being longer than the upper pivoting arm, being in particular approximately twice its length and being hinged so as to pivot about axes in the longitudinal direction of the vehicle by its ends directly to the top of said runner-carrying arm while the upper pivoting arm is linked to a lower pivot on the runner-carrying arm by means of a horizontal lever, whose end furthest from said runner-carrying arm pivots about longitudinally oriented axes at the corresponding end of the upper transverse arm by means of another lever which is hinged at an intermediate point so as to pivot about a longitudinal axis, to an intermediate point on the lower transverse arm, between its pivoting ends and its mid point. Other features further improving the snow vehicle according to claim 1 are the subject of the dependent claims. The particular features of the invention, and the advantages arising therefrom, will appear more in detail from the description of some preferred embodiments illustrated by way of examples in the accompanying drawings, in which: Fig. 1 is a lateral elevation of the frame of a snowmobile/skibob according to the invention. Fig. 2 is a front view of the front supporting means of the front runners of the frame according to Figs. 1 and 3. Fig. 3 is a view from above, partly in section, of the supporting means according to Fig. 2. Fig. 4 is a view of the supporting means of the rear runners of the frame illustrated in the previous figures. With reference to Figs. 1 to 4, a snowmobile/skibob frame consists of a load-bearing part 1 to which are attached two subframes 2, 3 for the front carriage and rear carriage. Mounted on the load-bearing part 1 of the frame is the saddle 4, while mounted rotatably at its front end is a handlebar 5. The subframe 2 of the front carriage consists of a system of pivoting arms hinged to each other which comprises two transverse arms 6, 8 positioned vertically one above the other and hinged at their mid points at 7 and 9 to the load-bearing part 1, in such a way that they can pivot about axes parallel with the longitidinal axis of the snowmobile. The lower pivoting arm 6 is longer than the upper pivoting arm 8, being in particular approximately twice its length, and is hinged so as to pivot about axes in the longitudinal direction of the snowmobile, at 10, 10', by its two ends directly to the top of a vertical runner-carrying arm 11, 11'. The upper pivoting arm 8 is linked to a lower pivot point 12, 12' on the runner-carrying arm 11, 11' via a horizontal lever 13, 13', whose end furthest from the runner-carrying arm 11, 11' pivots about longitudinally oriented axes at the corresponding end of the upper transverse arm 8 via another lever 14, 14', which is hinged at 15, 15', at an intermediate, preferably middle point so as to pivot about a longitudinal axis, to an intermediate point on the lower transverse arm 6, preferably to a middle point thereof, between its pivot 10, 10' and its pivot 7. Fixed to each runner-carrying arm 11, 11' is a transverse footrest bracket 16, 16' and below that a tubular cylindrical sleeve 17, 17', which is oriented vertically and inside which there is mounted, preferably on taper roller bearings and projecting below it a vertical rotatable stub shaft 18, 18'. Fixed to the free lower end of the stub shaft 18, 18' is a steering pulley 22, 22' with a downward axial supporting extension 19, 19' which is integral in rotation with said pulley. Said supporting extension is connected to the front runner 20, 20', which serves as a short ski, via a joint 21, 21' that pivots about a horizontal axis at right angles to the runner 20, 20'. Connected between an intermediate point on the front portion of each runner 20, 20' and the lower supporting extension 19, 19' is an elastic part 23, for example a helical spring that is loaded so as to exert a lifting action on the front portion of the runner 20, 20'. In particular, the vertical sleeve 17, 17' is integral with a plate 24, 24' that acts as a sheath stop and that covers the top of the pulley 22, 22', while the sleeve itself is fixed to the lower end of the runner-carrying arm 11, 11', by means of a pin oriented diametrically across it in a fork 111, 111' and is kept from pivoting in the transverse direction by means of a length-adjustable rod, for example a screw coupling 25, 25' that is connected between the plate 24, 24' and the runner-carrying arm 11, 11', in particular the top pivot 10, 10'. This construction enables the camber of the skis 20, 20' to be adjusted. In another improvement it is possible also to provide for adjustments to be made to the angle of attack of the skis 20, 20'. To this end the fork 111, 111' is so mounted on the remaining part of the runner-carrying arm 11, 11' as to be able to pivot about an axial pin 116 of the footrest bracket 16, which is perpendicular to the vertical mid plane of the frame, while locking means indicated 211 as a whole, for example a lock pin or the like, are provided to lock the fork 111, 111' at a predetermined angle of attack relative to the runner-carrying arm 11, 11'. The steering pulleys 22, 22' are engaged by respective pairs of control cables 26, 27, 26', 27'. Each cable 26, 27; 26', 27' of the two pairs engages the associated steering pulley 22, 22' of one of the runners 20, 20' from the opposite side relative to its pair and is attached at its end to the pulley in a peripheral clamping block 122, 122' that is positioned centrally when the runners 20, 20' are pointing in the longitudinal direction of the snowmobile/skibob. The cables may also be attached by means of four clamps (two per pulley) or by means of two clamps (one per pulley) and using two cables only. The control cables 26, 27, 26', 27', are guided by sheaths 126, 127, 126', 127' connected between end stops 28, 29 on the runner-carrying arms 11, 11' (plates 24, 24') and on the load-bearing part 1 of the frame. The four control cables 26, 27, 26', 27' are controlled by a control pulley 30 which is mounted so as to be able to rotate coaxially and integrally with the shaft 105 of the handlebar 5. The control pulley 30 has two parallel peripheral grooves 130, 230 for the control cables 26, 27 and 26', 27' respectively leading to the two steering pulleys 22, 22'. Each pair of control cables 26, 27 and 26', 27' engages the control pulley 30 on opposite sides of the pulley in the same way as on the steering pulleys 22, 22'. The ends of the cables 26, 27, 26', 27' are attached to the control pulley 30 by means of a clamp 330 that is positioned centrally on the peripheral edge of the control pulley 30 when the handlebar 5 is pointing straight ahead. Advantageously, in order that the steering action of the runners 20, 20' is in the same direction as the handlebar 5 is turned, the cables 26, 27 and 26', 27' may also be connected to the control pulley 30 in reverse to the way they are connected to the corresponding steering pulley 22, 22' (Fig. 3). The use of the steering pulleys 22, 22' and control pulley 30, as well as the guiding of the cables 26, 27, 26', 27' through sheaths connected between stationary end stops makes it possible to produce a mechanically rigid steering system with no play. In any steering position the take-up of the cable by the pulleys 22, 22', 30 means that the runner is efficiently held in the steering position by the opposing forces exerted by the two cables 26, 27 and 26', 27'. The members by which the runners 20, 20' are steered may of course also be constructed in other ways. One alternative embodiment uses semicircular pulleys in place of the circular pulleys 22, 22', 30. The cables can also be guided without use of sheaths or the like, but by means of one or more guide pulleys. Furthermore, if the system does not enable both cables of each pair connected to one runner to be simultaneously kept under tension, it is possible to use cable tensioning means acting automatically to take up any slack. A subframe 3 forming a rear carriage projects from, and is hinged to by means of two parallel longitudinal members 32 positioned vertically one above the other, the load-bearing part 1 of the frame. The longitudinal members 32 are hinged at 31, to pivot about mutually parallel transverse axes, on the load-bearing part 1 of the frame. The end portion hinged to the load-bearing part 1 of the frame is guided laterally for a certain predetermined length between two mutually parallel vertical guide plates 33. The inside of the these guide plates 33 is coated with an antifriction material such as teflon or the like. This enables transverse stresses on the pivot pin 31 to be reduced, avoiding twisting or a certain transverse swaying of the rear carriage 3. In an improvement in order to increase the lateral guiding of the longitudinal members 32, the latter possess a longitudinal projection 132 at the forward end past the pivot 31 that is also held between the two guide plates 33. Preferably, in order further to enhance the suppression of the transverse twisting and/or swinging of the rear carriage, the end portion of the longitudinal members 32 held between the two guide plates 33 may also possess transverse fins 232 that extend in the vertical plane and for strengthening the longitudinal members at the point of pivoting 31, 31' and of widening of the surface of the members 32 where they bear against the guide plates 33. The rear end of the longitudinal members 32 is hinged to the rear carriage subframe 3 in much the same way as has been described in relation to their hinging to the load-bearing part 1 of the frame. The rear end portions of the longitudinal members 32 are hinged at 31' and are guided between two parallel guide plates 33' which are sometimes laterally displaced because of the damping effect; the longitudinal members 32 are held between them for a certain length. These end portions may possess both longitudinal projections 132' and transverse wider portions 232' in the vertical plane. The elastic suspension of the load-bearing frame part 1, on which the saddle 4 is rigidly mounted, relative to the rear carriage is provided by a suspension spring 41 with a damper 40 joined between the load-bearing frame part 1 and the longitudinal member 32 in an area underneath the saddle 4. In particular it is supported with a rear end portion of approximately half its length projecting, and the suspension 40, 41 is hinged with one end near the middle of the saddle 4, approximately at the point of connection to the load-bearing part 1 of the frame and with the other end at a point on the upper longitudinal member 32 underneath the rear end of the saddle 4. In Fig. 1 there is mounted on the two rear guide plates 33' forming the rear carriage subframe 3 a motor unit 81 that drives a central longitudinal caterpillar track 80 coupled to the underside of the motor unit in an articulated manner. In Figs. 4 and 11, the rear carriage 3 is constructed in the form of an articulated parallelogram. The central vertical upright 34 fixed to the two rear guide plates 33' is hinged to two or more (in particular two) vertical lateral uprights 35, 35' carrying the runners, by means of two or more (in particular four) cross members 36, 360, 36', 360' which are hinged in their centres at 37, 37' to the top and bottom ends of the central upright 34. The cross members 36, 360, 36', 360' are hinged at their free ends respectively to the top ends of the two runner-carrying uprights 35, 35' and at a point situated at the same level as the lower pivot 37' to the central upright 34. In addition, in order to confer a degree of stiffness and ensure an auxiliary force for returning the articulated parallelogram to its right-angled rest position (as shown), elastic parts 38, 38' for example helical springs, are provided between the upper pivot point 37 joining the cross member 36 to the central upright and the diagonally opposite lower pivot points joining the lower cross member 36' to the runner-carrying uprights 35, 35'. The runner-carrying uprights 35 and 35' extend downwards past the central upright 34 and to these there are hinged, in the same way as to the front runners 20, 20', or to the caterpillar track 80, by means of joints 21, the runners 39, 39', e.g. in the form of skis or powered caterpillar tacks, while in both cases the runners 39, 39' and/or caterpillar tracks may be secured to an elastic lifting part similar to the part 3 for the front runners 20, 20'. This arrangement means that if the equipment leaves the ground, the runner does not dig into the snow when it strikes it again, since the raising of the front end while off the ground guarantees a correct position when it next impacts the ground. If the rear carriage 3 carries two runners 39, 39', it is possible to provide one or more powered caterpillar tracks in an intermediate position of the vehicle for propulsion. By adopting similar means to those used on the front runners 20, 20', it is of course possible to make the rear runner(s)/caterpillar track(s) 39, 39' steerable as well. In this case the rear runners 39, 39' can be made to execute a steering movement in phase or out of phase with the movement of the front runners 20, 20'. The construction described earlier for the frame of the snowmobile/skibob and steering means may also be applied in similar fashion to different configurations of runners, as for example where only three points of support on the ground are provided, two at the front and one at the back, or one at the front and two at the back, it being possible for these points of support to consist either entirely or in combination of skis/powered tracks or entirely of powered wheels or the like.

Claims: Snow vehicle comprising a load-bearing frame (1) and two ski-like parallel runners (20, 20') which are connected with the load-bearing frame by means of runner carrying arms (11, 11') in such a way that they can be steered and/or tilted by means of a control shaft (105) which can be rotated manually through hand grip means (10) and is connected by means of a transmission system with a steering and/or tilting shaft (18, 18') fixed to each runner (20, 20') and rotatably supported by the associated runner-carrying arm (11, 11'), the said transmission system comprising for each runner (20, 20') a pair of opposing transmission cables (26, 27; 26', 27') which engage on opposite sides of the longitudinal axis of the vehicle a control pulley (30) rotating integrally with the control shaft (105), said cables being connected on opposite sides of the longitudinal axis of the associated runner (20, 20') with an actuating pulley (22, 22') that rotates integrally with the steering and/or tilting shaft (18, 18') of the runner (20, 20'), characterized in that the runner-carrying arms (11, 11') are supported at the transverse ends of a front carriage subframe (2) in the form of an articulated parallelogram which comprises two transverse arms (6, 8) positioned vertically one above the other and hinged at their mid points (7, 9) to the load-bearing part (1) of the frame, in such a way that they can pivot about axes parallel with the longitudinal axis of the vehicle, the lower longitudinal arm (6) being longer than the upper pivoting arm (8), being in particular approximately twice its length and being hinged so as to pivot about axes in the longitudinal direction of the vehicle by its ends (10, 10') directly to the top of said runner-carrying arms (11, 11'), while the upper pivoting arm (8) is linked to a lower pivot (12, 12') on the runner carrying-arm (11, 11') by means of a horizontal lever (13, 13'), whose end furthest from said runner-carrying arm (11, 11') pivots about longitudinally oriented axes at the corresponding end of the upper transverse arm (8) by means of another lever (14, 14'), which is hinged at an intermediate point (15, 15'), so as to pivot about a longitudinal axis, to an intermediate point on the lower transverse arm (6), between its pivoting ends (10, 10') 10') and its mid point (7). Vehicle according to Claim 1, characterized in that fixed to each vertical runner-carrying arm (11, 11') is a transverse footrest bracket (16, 16') and below that a tubular cylindrical sleeve (17, 17') which is oriented vertically and inside which there is mounted, preferably on taper roller bearings and projecting below it, the associated vertical rotatable steering shaft (18, 18') fixed to the lower free end of which is the associated actuating pulley (22, 22') with a downward axial supporting extension (19, 19') which is integral in rotation with said pulley, which supporting extension (19, 19') is connected to the corresponding runner (20, 20') by means of a joint (21, 21') that pivots about a horizontal axis at right angle to said runner (20, 20'). Vehicle according to Claim 2, characterized in that the vertical sleeve (17, 17') supporting the steering shaft (18, 18') for the actuating pulley (22, 22') is supported so as to pivot at right angles to the longitudinal axis of the vehicle in a fork (111, 111') of the runner-carrying arm (11, 11') by means of a longitudinal diametrical pin and is kept from pivoting freely in the transverse direction of the vehicle while being adjustable relative to the transverse inclination, i.e. to the camber, by means of a length-adjustable rod, for example a screw coupling (25, 25'), connected between a lower plate (24, 24') integral with the vertical sleeve (17, 17') and said runner-carrying arm (11, 11'). Vehicle according to Claim 2 or 3, characterized in that the runner-carrying arm (11, 11') is formed in a stationary part comprising an articulation to the front carriage subframe (2) on which the fork part (111, 111') supporting the vertical sleeve (17, 17') is so mounted as to be able to pivot about a transverse horizontal axis, for example the axis (116) of the footrest bracket (16, 16'), while means are provided for locking together the two parts of the runner-carrying arm (11, 11') in a predetermined relative angular position, for example a mobile point (211). Vehicle according to Claim 1, characterized in that the front carriage subframe (2) is hinged directly on the load-bearing frame (1), while a rear carriage subframe (3) provided with ski-like runners (39, 39') or with powered caterpillar tracks 180) and powered wheels, is supported in such a way as to project backwards and be capable of vertical dispacement relative to the front carriage subframe (2). Vehicle according to Claim 5, characterized in that the rear carriage subframe (3) is hinged to the frame (1) by means of two central longitudinal members (32) positioned vertically one above the other and hinged (31, 31') so as to pivot about horizontal axes at right angles to the vehicle both to the rear carriage subframe (3) and to the frame (1), while the opposite ends of the longitudinal members (32) are guided laterally between two vertcal plates (33, 33') separated by a gap and coated on the inside with an antifriction material. Vehicle according to Claim 6, characterized in that each longitudinal member (32) has on both its ends an axial projection (132, 132') past the pivot (31, 31') which is likewise guided between the two plates (33, 33'), while on each of their sides in contact with the guide plates (33, 33'), the longitudinal members (32) has transverse fins (232, 232') which increase the surface area in contact with the guide plates (33, 33') and strengthen the longitudinal members (32, 32') at the pivot points (31, 31'). Vehicle according to one or more of the preceding claims, characterized in that front and rear ski-like runners (20, 20', 39, 39') are hinged to the front carriage subframe (2) and rear carriage subframe (3) by means of joints (21), elastic means (23) being provided to act in such a way as to lift the front portion of the runners (20, 20', 39, 39') and lower their tail ends. Vehicle according to one or more of the preceding claims, characterized in that the load-bearing frame (1) supports a saddle (4) in a projecting position, while a suspension unit comprising a spring and a damper (40, 41) is interposed between a middle point of the saddle and a longitudinal member (32) beneath the same. Vehicle according to one or more of the preceding claims, characterized in that it is provided with means for adjusting the camber of the runners (20, 20', 39, 39') of the front carriage subframe (3).

Inventors: PERTILE LIANO, PERTILE, LIANO
Applicants: PERTILE LIANO, PERTILE, LIANO
Application year: 1994
Main classification: B62M27
IPC codes: B62M27, B62B3, B62B13